Metal nanoclusters (e.g. Pt, Pd, and Au) have been those of the most valuable catalysts that have been used in many catalytic fields of hydrogenation, fuel-cell technologies, and water splitting photo-catalytically, etc. In this mini review, the previous works from our group about the optical, electrical and catalytic properties of metal nanoclusters, such as Pt13, Pd13, and Au13, have been reviewed. Ab initio molecular dynamics simulation (AIMD) at a DFT (Density Functional Theory) level has been applied to simulate the catalytic properties. The results show that Pt13 and Pd13 nanocluster present interesting hydrogen reduction and molecular H2 desorption on the surface of the metal nanoclusters. An elementary hydrogen evolution mechanism on the metal nanocluster was established as Hads++Hads++ 2e-+ Mads→[Mads-Hads-Hads]→H2+ M (M metal). On the other hand, an Au nanocluster, which is protected by organic thiolate groups, was investigated by ab initio electron dynamics (AIED) calculation. The comparison between the protected and unprotected Au nanoclusters clarifies the contributions from Au core and organic thiolate ligands to the optical and electronic properties, such as photoexcitation, electron/hole relaxation, and energy dissipation, etc.